The present invention relates to an elevator drive sheave disposed on a hoisting machine onto which a main rope for suspending a car is wound, the elevator drive sheave being rotated by a driving force from a motor portion of the hoisting machine.
FIG. 10 is a side elevation showing a conventional elevator hoisting machine such as shown in Japanese Utility Model Publication No. SHO 59-12444, for example, partially sectioned. The elevator hoisting machine in the figure includes: a motor portion 1; a rotating shaft 2 rotated by this motor portion 1; a bearing portion 3 for supporting the rotating shaft 2; a drive sheave 4 rotated together with the rotating shaft 2; and an electromagnetic brake 5 for braking rotation of the drive sheave 4.
The drive sheave 4 includes: a rope groove portion 4a onto which a main rope (not shown) is wound; and a brake drum portion 4b braked by the electromagnetic brake 5.
In a conventional elevator hoisting machine such as described above, it has been necessary to perform correction work on the rope groove portion 4a since the rope groove portion 4a is abraded by friction with the main rope. It has been necessary to perform correction work on the rope groove portion 4a particularly frequently when the drive sheave 4 is disposed outdoors due to the effects of weather and dust.
Since correction work of this kind is performed by removing the entire drive sheave 4 from the hoisting machine, a great deal of time and cost have been required, and operating efficiency of such elevators has also been reduced.
In regard to this, FIG. 11 is a front elevation showing part of another example of a conventional drive sheave, and FIG. 12 is a cross section taken along line XIIxe2x80x94XII in FIG. 11.
The drive sheave in the figures includes a sheave body 6 and a plurality of divided segments 7. A brake drum portion 6a is disposed on the sheave body 6. A rope groove portion 7a is disposed on the divided segments 7. The divided segments 7 are fixed to the sheave body 6 by a plurality of radial bolts 8 and a plurality of axial bolts 9.
Using a drive sheave of this kind, since it is sufficient simply to remove the divided segments 7 from the sheave body 6 when performing correction work on the rope groove portion 7a without removing the sheave body 6 from the rotating shaft, the correction work can be performed easily in a short period of time, enabling costs to be reduced and also enabling reductions in the operating efficiency of the elevator to be prevented.
However, in a conventional drive sheave of this kind, parts construction is complicated because of transmission of torque between the divided segments 7 and the sheave body 6, positioning of the divided segments 7 in an axial direction, etc., and complicated machining has been required on the parts, increasing costs.
The present invention aims to solve the above problems and an object of the present invention is to provide an elevator drive sheave enabling correction work on a rope groove portion to be performed easily and enabling costs to be reduced by a simple construction.
According to one aspect of the present invention, there is provided an elevator drive sheave disposed on a hoisting machine onto which a main rope for suspending a car is wound, the elevator drive sheave being rotated by a driving force from a motor portion of the hoisting machine, wherein the elevator drive sheave includes: a sheave body having a cylindrical main body outer circumferential surface; a plurality of divided segments divided in a circumferential direction of the sheave body, each mounted to the main body outer circumferential surface and formed with a rope groove portion into which the main rope is inserted; and a torque transmission mechanism in which a plurality of keys are interposed between the sheave body and the divided segments for positioning the divided segments in a circumferential direction relative to the sheave body and transmitting torque between the sheave body and the divided segments, a contact surface being disposed on the divided segments for positioning the divided segments in an axial direction relative to the sheave body by being placed in contact with an axial end surface of the sheave body.